const user1 = { age: 11 }
const user2 = { age: 22 }
const user3 = { age: 33 }

const nameList = [ user1.age, user2.age, user3.age ]

// function fn () {
//   num1 = 1
//   num2 = 2
// }

function fn () {
  const num1 = 1
  const num2 = 2
}
fn()

function fn1 () {
  const obj1 = {}
  const obj2 = {}

  // 对象之间互相指引，即使在方法调用之后，引用计数也依然无法将其置为0
  obj1.name = obj2
  obj2.name = obj1

  return 'test code'
}
fn1()